package com.nowcoder.topic.dfs.simple;

/**
 * NC13 二叉树的最大深度
 * @author d3y1
 */
public class NC13{
    private int result = 0;

    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 程序人口
     *
     * @param root TreeNode类
     * @return int整型
     */
    public int maxDepth (TreeNode root) {
        return solution1(root);
//        return solution2(root);
    }

    /**
     * dfs
     * @param root
     * @return
     */
    private int solution1(TreeNode root){
        return depth(root);
    }

    /**
     * 递归
     * @param root
     * @return
     */
    private int depth(TreeNode root){
        if(root == null){
            return 0;
        }

        return Math.max(depth(root.left), depth(root.right))+1;
    }

    /**
     * dfs
     * @param root
     * @return
     */
    private int solution2(TreeNode root){
        operate(root, 0);

        return result;
    }

    /**
     * 递归
     * @param root
     * @param level
     */
    private void operate(TreeNode root, int level){
        result = Math.max(result, level);

        if(root == null){
            return;
        }

        operate(root.left, level+1);
        operate(root.right, level+1);
    }

    private class TreeNode {
        int val = 0;
        TreeNode left = null;
        TreeNode right = null;

        public TreeNode(int val) {
            this.val = val;
        }
    }
}